diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..42ee230
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,134 @@
+# vscode
+.vscode/
+wandb/
+.DS_Store
+
+# Byte-compiled / optimized / DLL files
+__pycache__/
+*.py[cod]
+*$py.class
+
+# C extensions
+*.so
+
+# Distribution / packaging
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+pip-wheel-metadata/
+share/python-wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+MANIFEST
+
+# PyInstaller
+#  Usually these files are written by a python script from a template
+#  before PyInstaller builds the exe, so as to inject date/other infos into it.
+*.manifest
+*.spec
+
+# Installer logs
+pip-log.txt
+pip-delete-this-directory.txt
+
+# Unit test / coverage reports
+htmlcov/
+.tox/
+.nox/
+.coverage
+.coverage.*
+.cache
+nosetests.xml
+coverage.xml
+*.cover
+*.py,cover
+.hypothesis/
+.pytest_cache/
+
+# Translations
+*.mo
+*.pot
+
+# Django stuff:
+*.log
+local_settings.py
+db.sqlite3
+db.sqlite3-journal
+
+# Flask stuff:
+instance/
+.webassets-cache
+
+# Scrapy stuff:
+.scrapy
+
+# Sphinx documentation
+docs/_build/
+
+# PyBuilder
+target/
+
+# Jupyter Notebook
+.ipynb_checkpoints
+
+# IPython
+profile_default/
+ipython_config.py
+
+# pyenv
+.python-version
+
+# pipenv
+#   According to pypa/pipenv#598, it is recommended to include Pipfile.lock in version control.
+#   However, in case of collaboration, if having platform-specific dependencies or dependencies
+#   having no cross-platform support, pipenv may install dependencies that don't work, or not
+#   install all needed dependencies.
+#Pipfile.lock
+
+# PEP 582; used by e.g. github.com/David-OConnor/pyflow
+__pypackages__/
+
+# Celery stuff
+celerybeat-schedule
+celerybeat.pid
+
+# SageMath parsed files
+*.sage.py
+
+# Environments
+.env
+.venv
+env/
+venv/
+ENV/
+env.bak/
+venv.bak/
+
+# Spyder project settings
+.spyderproject
+.spyproject
+
+# Rope project settings
+.ropeproject
+
+# mkdocs documentation
+/site
+
+# mypy
+.mypy_cache/
+.dmypy.json
+dmypy.json
+
+# Pyre type checker
+.pyre/
diff --git a/examples/dueling_navix_empty.py b/examples/dueling_navix_empty.py
index 1808f13..ca8a411 100644
--- a/examples/dueling_navix_empty.py
+++ b/examples/dueling_navix_empty.py
@@ -30,7 +30,7 @@ def main(argv):
 
     # environment
     env = nx.environments.Room(5, 5, 100, observation_fn=nx.observations.categorical)
-    env = helx.environment.to_helx(env)  # type: ignore
+    env = helx.envs.interop.to_helx(env)
 
     # optimiser
     optimiser = optax.rmsprop(
diff --git a/helx/agents/dqn.py b/helx/agents/dqn.py
index 9bff670..8b5d3c2 100644
--- a/helx/agents/dqn.py
+++ b/helx/agents/dqn.py
@@ -29,7 +29,6 @@
 from helx.base.mdp import TERMINATION, Timestep
 from helx.base.memory import ReplayBuffer
 from helx.base.spaces import Discrete
-from helx.base import losses
 from .agent import Agent, HParams, Log, AgentState
 
 
diff --git a/helx/agents/dueling_dqn.py b/helx/agents/dueling_dqn.py
index c22a4ef..2db387d 100644
--- a/helx/agents/dueling_dqn.py
+++ b/helx/agents/dueling_dqn.py
@@ -12,7 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 from __future__ import annotations
-from functools import partial
 
 import jax.numpy as jnp
 import optax
@@ -36,6 +35,9 @@ class DuelingDQNState(DQNState):
 
 
 class DuelingDQN(DQN):
+    """Dueling DQN agent as described in https://arxiv.org/abs/1511.06581
+    Uses the average operator version to combine the advantage and value functions."""
+
     hparams: DuelingDQNHParams = struct.field(pytree_node=True)
     optimiser: optax.GradientTransformation = struct.field(pytree_node=True)
     critic: nn.Module = struct.field(pytree_node=True)
@@ -52,7 +54,10 @@ def create(
                 backbone,
                 Split(2),
                 Parallel((nn.Dense(1), nn.Dense(hparams.action_space.maximum))),  # v, A
-                Merge(partial(jnp.sum, axis=-1)) # q = v + A
+                Merge(
+                    lambda inputs: inputs[0]
+                    + (inputs[1] - jnp.mean(inputs[1], axis=-1))
+                ),  # q = v + (A - mean(A))
             ]
         )
         return DuelingDQN(
diff --git a/helx/base/modules.py b/helx/base/modules.py
index aaf4a67..b338c4f 100644
--- a/helx/base/modules.py
+++ b/helx/base/modules.py
@@ -12,14 +12,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 from __future__ import annotations
-from functools import partial
 
+from functools import partial
 from typing import Callable, Sequence, Tuple
 
-import flax.linen as nn
+from jax import Array
 import jax.numpy as jnp
 import jax.tree_util as jtu
-from jax import Array
+import flax.linen as nn
 
 
 class Split(nn.Module):
diff --git a/helx/envs/__init__.py b/helx/envs/__init__.py
index 0abeeb0..74454f9 100644
--- a/helx/envs/__init__.py
+++ b/helx/envs/__init__.py
@@ -24,5 +24,5 @@
     gymnasium,
     gymnax,
     interop,
-    # navix
+    navix
 )
diff --git a/requirements.txt b/requirements.txt
index 04bba32..78f535b 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -21,4 +21,5 @@ minigrid
 procgen
 gymnax
 brax
+navix
 wandb
\ No newline at end of file